Police holding Ray Gosling, the TV reporter arrested on suspicion of murder after admitting to killing a dying lover, have extended their questioning of him until at least 7.45pm tonight.

Gosling, 70, spent last night in a cell at Oxclose Lane police station in Nottingham, and was yesterday questioned on four occasions by murder detectives investigating the killing of the unnamed young man, which is understood to have taken place about 20 years ago.

Further interviews are expected to take place today as the investigation widens. Police have searched several properties, including Gosling's home in a Nottingham sheltered housing complex, but Gosling has not been charged.

The questioning could be extended until Sunday morning, but Gosling's solicitor, Digby Johnson, said he hoped his client would be released, possibly on police bail, much sooner. Johnson said the last 24 hours in custody had "taken its toll" on Gosling, although he was being well looked after. He is understood to be standing firm by his resolution to withhold from the police the name of the victim, where he killed him and when – "even under torture".

Police are today understood to be interviewing at least one of his friends who knew him at the time of the killing. Yesterday it emerged that friends had known for more than a decade that Gosling had killed his dying lover.

Gosling had claimed to have kept the killing secret, but close friends have revealed he confided in a small number of confidants them. They did not tell police because they considered the actions he described to be assisted suicide.

They said he told them the killing took place about 20 years ago and that, although Gosling has so far described the unnamed victim as "a bit on the side", he knew him before he contracted Aids and during his illness. One friend also revealed that Gosling's pact with the man was two-way so that "if either of them were in a bad situation the other would do it".

Gosling was arrested at his home shortly after dawn yesterday after he admitted to the killing on TV on Monday night. Friends said Gosling had not expected to be arrested and had planned to travel to Barrow-in-Furness this week to make a Radio 4 documentary.

Detectives have examined the unedited footage of Gosling's feature for BBC East Midlands TV on Monday to establish if there was any collusion with members of the crew who may have been told details of the crime. They are understood to be satisfied by Gosling's account that he decided to make the confession "there and then" when standing beside the grave of his long-term boyfriend, Bryn Allsop, for a piece to camera.

"He told me about it a long time ago," said Alan Horsfall, a fellow gay rights campaigner who has known Gosling for 40 years. "It came up in passing, he told me about it and that was that. He didn't make a big issue about it. It was some years after the event that he told me. I accepted it as assisted suicide.

"It was an act of great bravery, especially as he did it in a public place. I know the guy was in a bad state and Ray said they had a previous pact that if either of them was in a bad situation the other would do it."

Horsfall said it had not occurred to him to contact police and said he did not know the victim's name or where it happened. "He isn't a natural killer," he said. "It never occurred to me it was a crime."

"I was shocked but he described it in terms of an assisted suicide," said Bob Dickinson, a Radio 4 producer whom Gosling told about the killing last month. "I have known Ray for a long time, but he doesn't strike me as a murderer. He is a humane person. He is obsessed by the importance of ordinary people's lives. He knew he was going to use his own life as a story. He thought this could be another episode in his story."

The BBC defended its decision to broadcast the confession. "We believe we have handled the report sensitively and appropriately," a spokesman said yesterday. "We kept [Gosling] fully informed about our representation of his story in the report and he understood that a revelation of this nature could have a number of consequences.

"The BBC is under no legal obligation to refer the matter to the police in these circumstances, and since transmission we have been approached by the police and are co-operating fully."